Certain reactors require process gases to be heated for use therein. The reactor may include a susceptor stack in which the process gases are heated and reacted with one another. One particular type of reactor that requires such heating relates to the production of trichlorosilane (SiHCl3) and hydrogen chloride using tetrachlorosilane (SiCl4) and hydrogen (H2) at elevated temperatures to facilitate a hydrogenation reaction of the tetrachlorosilane. The resulting trichlorosilane may be used to produce, or be purified to ultimately produce, high purity (e.g., electronic and/or solar grade) polysilicon.
In order to obtain the above-described reaction, the process gases are heated with a heater element that is located outside of the susceptor. The heater element heats an outer wall of the susceptor and the heat transfer occurs via radiant and convective energy. The heat energy then conducts through the susceptor wall and into the process gas by way of convective and conductive heat transfer.
The above-described externally located heater element results in roughly half of the radiant heat generated actually facing the susceptor stack, thereby resulting in less than optimal heat transfer efficiency. Additionally, operation of the heater element in the above-described configuration requires maintaining the heater element at a temperature that leads to increased structural stress, thereby reducing component life.